openrisc: Add HAVE_REGS_AND_STACK_ACCESS_API support

Support for HAVE_REGS_AND_STACK_ACCESS_API needed for restartable
sequences.

The implementation has been copied from riscv and tested with the
restartable sequences self tests.

Note, pt-regs members are 'long' on openrisc which require casts for the
api, someday we should try to update these to be 'unsigned long' as
that's what they really are.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
[stafford: Updated commit message]
Signed-off-by: Stafford Horne <shorne@gmail.com>

diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
index 3d053e0b59f4b200c17f686ab9b991b8c065ac5e..607a59bc2a22d823e8f0bfa1e21a505c91005604 100644 (file)
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -27,6 +27,7 @@ config OPENRISC
        select HAVE_PCI
        select HAVE_UID16
        select HAVE_PAGE_SIZE_8KB
+       select HAVE_REGS_AND_STACK_ACCESS_API
        select GENERIC_ATOMIC64
        select GENERIC_CLOCKEVENTS_BROADCAST
        select GENERIC_SMP_IDLE_THREAD

diff --git a/arch/openrisc/include/asm/ptrace.h b/arch/openrisc/include/asm/ptrace.h
index 1da3e66292e21ac885b3de50fb24b5cf1182bd62..e5a282b670757b9b6283aa424dfc85c48c617217 100644 (file)
--- a/arch/openrisc/include/asm/ptrace.h
+++ b/arch/openrisc/include/asm/ptrace.h
@@ -17,6 +17,7 @@
 
 #include <asm/spr_defs.h>
 #include <uapi/asm/ptrace.h>
+#include <linux/compiler.h>
 
 /*
  * Make kernel PTrace/register structures opaque to userspace... userspace can
@@ -42,6 +43,36 @@ struct pt_regs {
                        /* Named registers */
                        long  sr;       /* Stored in place of r0 */
                        long  sp;       /* r1 */
+                       long  gpr2;
+                       long  gpr3;
+                       long  gpr4;
+                       long  gpr5;
+                       long  gpr6;
+                       long  gpr7;
+                       long  gpr8;
+                       long  gpr9;
+                       long  gpr10;
+                       long  gpr11;
+                       long  gpr12;
+                       long  gpr13;
+                       long  gpr14;
+                       long  gpr15;
+                       long  gpr16;
+                       long  gpr17;
+                       long  gpr18;
+                       long  gpr19;
+                       long  gpr20;
+                       long  gpr21;
+                       long  gpr22;
+                       long  gpr23;
+                       long  gpr24;
+                       long  gpr25;
+                       long  gpr26;
+                       long  gpr27;
+                       long  gpr28;
+                       long  gpr29;
+                       long  gpr30;
+                       long  gpr31;
                };
                struct {
                        /* Old style */
@@ -66,16 +97,56 @@ struct pt_regs {
 /* TODO: Rename this to REDZONE because that's what it is */
 #define STACK_FRAME_OVERHEAD  128  /* size of minimum stack frame */
 
-#define instruction_pointer(regs)      ((regs)->pc)
+#define MAX_REG_OFFSET offsetof(struct pt_regs, orig_gpr11)
+
+/* Helpers for working with the instruction pointer */
+static inline unsigned long instruction_pointer(struct pt_regs *regs)
+{
+       return (unsigned long)regs->pc;
+}
+static inline void instruction_pointer_set(struct pt_regs *regs,
+                                          unsigned long val)
+{
+       regs->pc = val;
+}
+
 #define user_mode(regs)                        (((regs)->sr & SPR_SR_SM) == 0)
 #define user_stack_pointer(regs)       ((unsigned long)(regs)->sp)
 #define profile_pc(regs)               instruction_pointer(regs)
 
+/* Valid only for Kernel mode traps. */
+static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
+{
+       return (unsigned long)regs->sp;
+}
+
 static inline long regs_return_value(struct pt_regs *regs)
 {
        return regs->gpr[11];
 }
 
+extern int regs_query_register_offset(const char *name);
+extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
+                                              unsigned int n);
+
+/**
+ * regs_get_register() - get register value from its offset
+ * @regs:      pt_regs from which register value is gotten
+ * @offset:    offset of the register.
+ *
+ * regs_get_register returns the value of a register whose offset from @regs.
+ * The @offset is the offset of the register in struct pt_regs.
+ * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
+ */
+static inline unsigned long regs_get_register(struct pt_regs *regs,
+                                             unsigned int offset)
+{
+       if (unlikely(offset > MAX_REG_OFFSET))
+               return 0;
+
+       return *(unsigned long *)((unsigned long)regs + offset);
+}
+
 #endif /* __ASSEMBLY__ */
 
 /*

diff --git a/arch/openrisc/kernel/ptrace.c b/arch/openrisc/kernel/ptrace.c
index 5091b18eab4c36ea4c6d40636d8e4af4e6e2f905..8430570d0620b705f761b0c14118b45ae4512d15 100644 (file)
--- a/arch/openrisc/kernel/ptrace.c
+++ b/arch/openrisc/kernel/ptrace.c
@@ -160,6 +160,102 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task)
  * in exit.c or in signal.c.
  */
 
+struct pt_regs_offset {
+       const char *name;
+       int offset;
+};
+
+#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
+#define REG_OFFSET_END {.name = NULL, .offset = 0}
+
+static const struct pt_regs_offset regoffset_table[] = {
+       REG_OFFSET_NAME(sr),
+       REG_OFFSET_NAME(sp),
+       REG_OFFSET_NAME(gpr2),
+       REG_OFFSET_NAME(gpr3),
+       REG_OFFSET_NAME(gpr4),
+       REG_OFFSET_NAME(gpr5),
+       REG_OFFSET_NAME(gpr6),
+       REG_OFFSET_NAME(gpr7),
+       REG_OFFSET_NAME(gpr8),
+       REG_OFFSET_NAME(gpr9),
+       REG_OFFSET_NAME(gpr10),
+       REG_OFFSET_NAME(gpr11),
+       REG_OFFSET_NAME(gpr12),
+       REG_OFFSET_NAME(gpr13),
+       REG_OFFSET_NAME(gpr14),
+       REG_OFFSET_NAME(gpr15),
+       REG_OFFSET_NAME(gpr16),
+       REG_OFFSET_NAME(gpr17),
+       REG_OFFSET_NAME(gpr18),
+       REG_OFFSET_NAME(gpr19),
+       REG_OFFSET_NAME(gpr20),
+       REG_OFFSET_NAME(gpr21),
+       REG_OFFSET_NAME(gpr22),
+       REG_OFFSET_NAME(gpr23),
+       REG_OFFSET_NAME(gpr24),
+       REG_OFFSET_NAME(gpr25),
+       REG_OFFSET_NAME(gpr26),
+       REG_OFFSET_NAME(gpr27),
+       REG_OFFSET_NAME(gpr28),
+       REG_OFFSET_NAME(gpr29),
+       REG_OFFSET_NAME(gpr30),
+       REG_OFFSET_NAME(gpr31),
+       REG_OFFSET_NAME(pc),
+       REG_OFFSET_NAME(orig_gpr11),
+       REG_OFFSET_END,
+};
+
+/**
+ * regs_query_register_offset() - query register offset from its name
+ * @name:      the name of a register
+ *
+ * regs_query_register_offset() returns the offset of a register in struct
+ * pt_regs from its name. If the name is invalid, this returns -EINVAL;
+ */
+int regs_query_register_offset(const char *name)
+{
+       const struct pt_regs_offset *roff;
+
+       for (roff = regoffset_table; roff->name != NULL; roff++)
+               if (!strcmp(roff->name, name))
+                       return roff->offset;
+       return -EINVAL;
+}
+
+/**
+ * regs_within_kernel_stack() - check the address in the stack
+ * @regs:      pt_regs which contains kernel stack pointer.
+ * @addr:      address which is checked.
+ *
+ * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
+ * If @addr is within the kernel stack, it returns true. If not, returns false.
+ */
+static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
+{
+       return (addr & ~(THREAD_SIZE - 1))  ==
+               (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
+}
+
+/**
+ * regs_get_kernel_stack_nth() - get Nth entry of the stack
+ * @regs:      pt_regs which contains kernel stack pointer.
+ * @n:         stack entry number.
+ *
+ * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
+ * is specified by @regs. If the @n th entry is NOT in the kernel stack,
+ * this returns 0.
+ */
+unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
+{
+       unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
+
+       addr += n;
+       if (regs_within_kernel_stack(regs, (unsigned long)addr))
+               return *addr;
+       else
+               return 0;
+}
 
 /*
  * Called by kernel/ptrace.c when detaching..